1. Field of the Invention
The invention relates to a rotary printing machine such as a web-fed rotary printing machine, having a printing unit comprised of a plurality of printing-unit cylinders at least one of which can be brought into and out of contact with a functional unit associated with a function needed to operate the printing unit.
2. Description of the Related Art
In the case of arrangements of the type present here, there are infeed movements between the printing-unit cylinders and the functional units associated with these. In the case of the known rotary printing machines, the infeed movements between mutually associated elements are generally implemented in each case by means of a pivoting movement limited by mechanical stops. The drawback in this case is that the stops have to be adjusted and readjusted in the event of changing conditions. The result is, therefore, a high operational outlay. Added to this is the fact that many conditions, such as the temperature of printing cylinders, change frequently or continuously, so that exact readjustment with tolerable effort is not even possible. The consequence of this is inaccurate setting, which has a detrimental effect on the achievable working result.
It is an object of the present invention to provide a rotary printing machine of the above-mentioned type while avoiding the disadvantages of the known arrangements and in which high operating convenience and accuracy are ensured.
This object is achieved by providing a rotary printing machine, in particular a webfed rotary printing machine, having at least one printing unit which comprises a plurality of printing-unit cylinders, of which at least one can be brought into and out of operative connection with at least one functional unit which is associated with a function needed to operate the printing unit, the functional unit being provided with a drive device, and fitted on a linear guide device. The functional unit is assigned a positioning device, which has a controller which can be fed with at least one position-dependent signal that can be generated by means of a sensor arrangement associated with the functional unit and by which the drive device can be controlled.
These measures make it possible to dispense with mechanical stops, so that the disadvantages associated with these are also advantageously dispensed with. The positioning device according to the invention advantageously permits exact positioning of the associated functional unit in any desired position, it being possible for automatic adaptation to changing conditions to take place. This advantageously also applies to changing cylinder diameters, which makes it easier to change format.
Other advantageous refinements and expedient developments of the higher-order measures can be made. For example, the functional unit can expediently be associated with sensor arrangements for determining the respective distance covered and the encounter with the associated printing-unit cylinder, it being possible for the output signals from the sensor arrangements to be fed to the controller. The combination of distance-based and point-based control results in particularly high accuracy when moving to a desired operating position.
The controller can advantageously be programmed in such a way that the functional unit can be moved into a desired operating position when the drive device is activated, starting from the position determined when it encounters the associated printing-unit cylinder. The position in which the functional unit encounters the associated printing-unit cylinder forms a zero point or reference point which the functional unit looks for in every case, so that an exact operating position can always be reached, irrespective of the position of this reference point. Moving the functional unit to a desired position also can involve a setting to a desired contact pressure or a desired gap width with respect to an associated printing-unit cylinder.
The sensor arrangement for determining the distance covered may expediently be associated with an incremental arrangement. In this case, digital values, which can easily be processed as data, automatically result.
A further advantageous refinement of the higher-order measures can consist in the sensor arrangement for determining the encounter between the functional unit and the associated printing-unit cylinder being designed as a strain detector associated with a part of the drive device which can be acted on by the contact pressure between functional unit and printing-unit cylinder. This detector advantageously supplies a signal which is an analog of the contact pressure. The result is therefore simultaneously a pressure sensor. This makes it easier to drive the drive device in order to reach an operating position, in which the functional unit is thrown with pressure onto the associated printing-unit cylinder. Setting the functional unit to a gap with respect to the associated printing-unit cylinder is, by contrast, expediently carried out as a function of distance.
In a further development of the higher-order measures, the controller, which is expediently designed as a programmable computer, can have a communications connection for a remote programming and/or monitoring device. This advantageously permits the rectification of maladjustments, etc., by using modern communication means, which results in extreme ease of maintenance and servicing.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.